What is the molarity of a potassium triiodide solution,KI₃(aq) ,if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.300 M thiosulfate solution,K₂S₂O₃(aq) ? The chemical equation for the reaction is
2 S₂O₃^2-(aq) + I₃^-(aq) → S₄O₆^2-(aq) + 3 I^-(aq) .

Question

Quizplus · Accepted Answer

The stoichiometry of the reaction shows that 2 moles of thiosulfate react with 1 mole of triiodide. Calculate moles of thiosulfate: 0.025 L * 0.300 M = 0.0075 moles. Therefore, moles of triiodide = 0.0075 / 2 = 0.00375 moles. Molarity of KI3 = 0.00375 moles / 0.030 L = 0.125 M.

What Is the Molarity of a Potassium Triiodide Solution,KI3(aq),if 30

What Is the Molarity of a Potassium Triiodide Solution,KI₃(aq),if 30